68 
Smith on Asteridia. 
and probably in all the similar forms and situations in which 
it occurs in the lower Confervae, &c. — is deposited around a 
nitrogenous nucleus. In Hydrodictyon the fact is very clear, 
that the central portion of the amylon-corpuscle is turned of 
a deep brown by iodine, or pink, by sulphuric acid and sugar 
(as was first pointed out to me by Mr. Huxley), and that at 
one time it exhibits no trace of starch in its composition, but 
that subsequently this nitrogenous nucleus becomes sur- 
rounded, not with an entire wall of starch, but apparently by - 
a cup-shaped deposit of that substance in which the nucleus 
lies imbedded, or from which it projects on the external 
aspect. Further observation of this and analogous pheno- 
mena may perhaps in time lead to a more satisfactory ex- 
planation of the genesis of starch than can at present 
possibly be given. It does not, at all events, contradict the 
notion of the vesicular nature of the starch-grain, but rather, 
as it seems to me, tends to confirm it ; for we have only to 
imagine the entire removal — as we may often witness the 
partial — of the central nucleus, when what remains, viz. the 
cup in which it was lodged, will very closely resemble some 
of the more open forms of starch-vesicles I have noticed in 
the paper. 
On the Stellate Bodies occurring in the Cells of Fresh-water 
ALGiE. By the Rev. William Smith, F.L.S. 
The third volume of the ' Transactions of the Microscopical 
Society,' containing, at p. 165, et seq,^ two papers by G. Shad- 
bolt, Esq., ' On the Sporangia of some of the Filamentous 
Fresh-water Algae,' has just been placed in my hands. 
The subject discussed in these papers having attracted my 
attention at various times, and being in possession of ad- 
ditional facts, some corroborative of Mr. Shad bolt's state- 
ments, and others which lead me to a conclusion widely 
different from that to which he has arrived, I have gladly 
embraced the opportunity, which the Society has accorded 
me, of bringing the following details under the attention of 
its members : — 
The accurate observations of one of the earliest and most 
successful students of this department of botany, M . Vaucher, 
of Geneva, have established the correct nature of the oval 
body, formed by conjugation in the filamentous Algae, w^hich 
this author has shown to be a true spore, each such body, 
formed by the union of two cells, giving birth, upon germina- 
